FIG. 1 schematically shows a Thin Film Transistor Liquid Crystal Display (TFT-LCD) in the prior art. As shown in FIG. 1, the TFT-LCD in the prior art comprises a light bar 1, a light guide plate 2, a brightness-enhancing film 3, a lower polarizer 4, an array substrate 5, a liquid crystal layer 6, a color filter substrate 7, an upper polarizer 8, and a reflective sheet 9. Liquid crystal molecules can be rotated through controlling a voltage that is applied to the liquid crystal layer 6, so that a polarization direction of a linearly polarized light that is emitted by a backlight module (the backlight module comprises the light bar 1, the light guide plate 2, the brightness-enhancing film 3, and the reflective sheet 9) can be changed after passing through the lower polarizer 4. Light with different colors can be formed after passing through the color filter substrate 7. Since the polarization direction of the light can form different angles with a light transmission axis of the upper polarizer 8, the strength of the light can be controlled, and a needed image can be displayed.
In the TFT-LCD in the prior art, the liquid crystal layer 6 cannot emit light itself, and thus the aforesaid backlight module is used to serve as a light source thereof. As a result, a color gamut of the LCD is relatively small.
FIG. 2 schematically shows an Organic Light Emitting Diode (OLED) display panel in the prior art. As shown in FIG. 2, the OLED display panel in the prior art comprises a glass substrate 10, an anode 11 (the anode 11 is mainly made of Indium Tin Oxide, i.e., ITO), an electron-hole injection layer 12, an electron-hole transmission layer 13, an organic blue light emitting layer 14, an organic red light emitting layer 15, an organic green light emitting layer 16, an electron transmission layer 17, an electron injection layer 18, and a cathode 19. As shown in FIG. 2, arrows refer to light exiting direction.
During the manufacturing procedure of the OLED display panel with this structure, a red organic light-emitting material, a blue organic light-emitting material, and a green organic light-emitting material should be vapor-plated on a large sized glass substrate in sequence. As a result, the qualified rate of the display panel is low, and the cost of the OLED display panel is relatively high.